Furnace structure for expanding heat-expandable ores



PANDABLE ORES March 28, 1967 WAGNER ET AL FURNACE STRUCTURE FOR EXPANDING HEAT-EX 4 Sheets-Sheet 1 Filed June 29, 1964 E 5 w: M 5W0 v W54 E N. Wm M;

March 28, 1967 WAGNER ET AL FURNACE STRUCTURE FOR EXPANDING HEAT-EXPANDABLE ORES 4 Sheets-Sheet 2 Filed June 29, 1964 flifef f, W GNEE OH S. Ana/M5 y n k u United States Patent 3,311,359 FURNACE STRUCTURE FGR EXPANDING HEAT-EXPANDABLE (IRES Albert E. Wagner, Simian-d, and John S. Adkins, Santa Monica, Caiif., assignors to Aden Supplies, Inc, Los Angeies, Calif, a corporation of California Filed June 29, E54, Ser. No. 378,818 12 Claims. (Cl. 263-34) This invention relates to improvements in ore processing and heating apparatus and, more particularly, to improved furnace structure for heating and expanding expandable ores.

Heretofore, it has been known to process, heat, and expand ores, such as perlite, in furnaces including flameheated, tubular ovens which are made to rotate while in an inclined position. In such furnaces, the ore is fed from storage into the upper end of the ovens while they are being rotated. The objective is to rotate the ovens at such a speed and angle that the ore particles upon reaching the lower ends of the ovens are expanded a desired amount.

Unfortunately, known ore expanding furnaces are characterized by numerous problems which limit the efficiency of ore expansion and materially increase the cost of the expanded ore products of the furnaces.

For example, it is common to extend the tubular ovens through opposite open ends of the surrounding furnace structure and to support the exposed ends of the oven for rotation within separate bearing assemblies. The ovens are heated by fiames from a plurality of burner nozzles stationed in the floor of the furnace structure along the sides of the ovens. Such an arraengment does not produce uniform longitudinal heating of the tubular ovens. Hence, expandable or particles passing through the oven are subjected to difierent temperatures along the oven and are prevented from achieving the desired or complete expansion.

Also, with use, the inside of the furnace structures becomes coated with brittle deposits of carbon and other foreign matter within the furnace structure. Frequently, these desposits become loosened and fall into the burner nozzles thereby clogging the nozzles. This materially interferes with the development of uniform flames within the furnace structure and requires periodic cleaning and replacement of the burner nozzles.

Moreover, as heat-expandable ore particles are fed down the tubular ovens, small portions of the ore expand, stick to and build up crusts on the inner surfaces of the ovens. The crust materially interferes with the proper heating of other ore particles and prevents the desired complete expansion of ore particles as they pass through the ovens.

In view of the foregoing, it is a general object of this invention to provide an improved furnace structure for expanding heat-expandable ores which overcomes the foregoing problems.

Another object of this invention is to provide a furnace structure for expanding heat-expandable ores including an improved furnace chamber design which insures uniform heating of a pair of tubular ovens stationed within the chamber.

A further object of this invention is to provide a furnace structure of the foregoing type including a burner mechanism with nozzles capable of evenly heating tubular ovens rotated within the furnace chamber of the structure without being subjected to clogging by foreign matter within the furnace.

Still another object of this invention is to provide a furnace structure for expanding heat-expandable ores within rotating tubular ovens including means for prevent- 3,3 1 1,35 9 Patented Mar. 28, 1967 ing the incrustation of ore particles on the inner surfaces of the tubular ovens.

A still further object of this invention is to provide a furnace of the foregoing type including air scouring means for the inner surfaces of the ovens as they rotate within the furnace.

The foregoing as well as other object-s and advantages of this invention will be more clearly understood from a reading of the following detailed description taken in connection with the accompanying drawings which set forth by way of illustration and example a particular embodiment of this invention.

In the drawings:

FIGURE 1 is an elevational View of an assembly for expanding heat-expandable ores showing the arrangement of components for storing the crushed ore in a storage hopper and initially heating and partially expanding the ore as it is fed int-o tilted notary ovens for expanding the ore, showing the means for selectively collecting lightweight expanded particles of the ore from the exhaust of the ovens and showing means for collecting and bagging the expanded particles;

FIGURE la is a fragmentary sectional side view of the feed mechanism for selectively and controllably feeding the ore from the feed hopper;

FIGURE 1b is a fragmentary front view of the feed mechanisms for selectively feeding ore from the storage hopper into the rotary ovens;

FIGURE 1c is a fragmentary side view of a preferred form of feed mechanism;

FIGURE 2 is a sectional side view of the furnace structure seen in FIGURE 1 showing the intemal construction of the furnace structure, the feed, discharge, and exhaust components associated with the furnace structure, and the mechanism for scouring the inner surfaces of the ovens stationed within the furnace structure;

FIGURE 3 is a vertical sectional view taken along the line 3-3 in FIGURE 2 showing further detail of the inner furnace construction, the position of the rotary ovens and the location of the burners for heating the same together with the manifolds for supplying fuel to the burners;

FIGURE 4 is a fragmentary front view taken along the line 44 in FIGURE 2 showing the drive means for operating the number of rotary ovens;

FIGURE 5 is a fragmentary front view of the furnace structure showing the drive means for operating the mechanism for scouring the inner surfaces of the rotary ovens;

FIGURE 6 is an expanded fragmentary sectional side elevation of the front end of the furnace structure showing in more detail the front end of the mechanism for scouring the inner surfaces of the ovens and the drive means for operating the scouring mechanism; and

FIGURE 7 is a sectional view of the scouring mechanism taken along the line 7-7 in FIGURE 6.

In the ore expansion assembly illustrated in FIGURE 1, crushed, heat-expandable ore, such as perlite, stored in a storage hopper It) is fed at a controlled rate by a plurality of ore feeders 12 and conveyor belts 14 to and through a vertical feed and initial expander 16 into a plurality of inclined rotary tubular ovens housed within a furnace structure I18. In the ovens, the ore is heated, expanded and discharged for collection in the pit 20 and by a recovery mechanism 22 for lightweight expanded ore particles exhausted from the ovens. The expanded ore in the pit is drawn into a collection hopper 24 and bagged for storage by a suitable bagging and conveyor mechanism 26.

More particularly, to feed the crushed ore from the storage hopper 10 at a controlled rate, the feeders 12 are secured over openings in the lower end of the hopper and each include a paddle wheel-shaped rotor 28. The rotors 28 are fixed to a shaft 29 extending through the feeders -12 and are rotated together by a drive mechanism 30 including a driven pulley 3-1 on the end of the shaft 29, a variable speed motor 32 supported by the framework 33 for the hopper 10, and a drive belt 34 passing over the driven pulley 3-1 and a pulley 35 fixed to the drive shaft of the motor.

As the rotors 28 turn within the feeders 12, the vanes of the rotors carry the crushed ore particles from the open ends of the hopper through the lower ends of the feeders where they fall by gravity onto the upper surfaces of the conveyor belts 14. Each conveyor belt 14 is stationed below a feeder 12 and passes around and between a pair of rollers 38 and 40. The rollers 38 are fixed to the drive shaft 44 of a variable speed motor 42 which is secured to the side of the framework 33. The rollers 40 are coupled for rotation to the structure of the initial expander 16. Hence, the ore particles dropping from the hopper 1-2 are simultaneously carried by the conveyor belts 14 into the upper end of the initial expander 16.

A preferred form of feed mechanism for feeding controlled quantities of ore particles from the hopper 10 to the initial expander 16 at a controlled or metered rate is illustrated in FIGURE 10. In the preferred form the feeder 12 comprise a plurality of vertical tubes 13 stationed for sliding vertical movement through openings in the lower end of the hopper 10. The tubes 13 are releasably locked within the openings by ring clamps extending from the hopper 10 around the tubes. By loosening the clamps 15 the tubes may be selectively positioned, one above each conveyor belt 14. Preferably the vertical displacement of the lower end of each tube from its associated belt 14 is the same. Since the belts 14 are driven at the same speed this insures that the same quantity of ore particles are fed into each rotary oven. More particularly, the ore particles passing through the tubes 13 pile on the belts 14 up to the lower ends of the tubes. The rate of conveyor belt travel to ward the initial expander 16, as controlled from the variable speed motor 42, then meters or controls the exact quantity of ore particles feed to the ovens.

Preferably, the initial expander 16 is of the type described in co-pending patent application entitled, Improvements in Apparatus for Expanding Heat-Expandable Ores," Ser. No. 378,819, filed June 29, 1964. Basically, the initial expander 16 comprises a chimney 46 passing hot gases from the furnace structure 18 upward about a plurality of vertical feed tubes 48 stationed within the chimney 46 and leading downward into the rotary ovens of the furnace structure. Each roller 40 extends through an opening in the chimney and is coupled to the side surfaces of one of the feed tubes 48. Hence, the ore particles on the conveyor belts 14 fall into the upper ends of the feed tubes 48 and pass downward into different rotary ovens. As the ore particles fall downward within the feed tubes, they are heated by the gases traveling upward through the surrounding chimney 46 and partially expand prior to their final expansion within the tubular ovens stationed within the furnace structure 18.

The furnace structure 18 housing the rotary ovens is most clearly illustrated in FIGURES 2 and 3 and includes a base member 50 having upwardly extending sidewalls 52 at opposite sides of the furnace structure and an upwardly extending partition 54 midway between the sidewalls. The partition 54 together with the sidewalls 52 supports upper arches 56 which together with the base 50 forms a pair of furnace chambers 58 and 60. Within each chamber the base 50 curves upward to a central longitudinally extending ridge such that each of the chambers in cross section resembles an inverted heart having left and right side lobes.

Stationed at the front and rear of the chambers 58 and 60 are front and rear walls 62 and 64. The front 4 wall 62 includes four holes 66, one to each side lobe of the chambers 58 and 60. The holes are located side by side and, as will be described, are each adapted to receive the open front end of a tubular oven for mounting within the furnace structure. Simliar to the front wall, the rear wall includes four holes 68, one for each side lobe of the chambers 58 and 60. Each hole 68 is aligned with and corresponds to a different hole 66 in the front wall 62 and is adapted to receive the rear end of a tubular oven within the furnace structure 18. In addition to the holes 68, the rear wall 64 also includes a pair of exhaust ports 70, one for each furnace chamber. The exhaust ports open into the holes 68 through the upper side of the rear wall 64. In line with the exhaust ports 70 are a pair of discharge ports 72 extending from the holes 68 through the lower sidl; of a rear wall 64.

The foregoing elements of the furnace structure 18 are composed of a refractory material such as firebrick and are held together by metal plates 74 extending along the bottom, right and left sides, and front and rear of the furnace structure. The plates 74 are secured together by a plurality of cross-connecting channel-shaped tie bars 76 which also extend along the front and rear ends and right and left sides of the furnace structure along the outside of the plates 74. The channel shape of the tie bars allows passage of air adjacent the plates 74 to assist in dissipating the heat from the furnace structure 18.

To position the furnace structure 18 at the desired angle of tilt, it is preferable to support the furnace structure on an axis located substantially under the middle portion of the structure so that the weight on one end of the furnace beyond the tilting axis substantially counter balances the weight of the furnace on the other side of the axis. For this purpose, and referring to FIGURES 2 and 3, bottom channels 78 are provided along the underside of the furnace structure 18. The channels 78 carry halfround sockets 80 midway along the furnace structure. Stationed opposite the sockets 80 are half-round sockets 82 supported on mounting blocks 84 atop a frame 86. Passing between half-round sockets 80' and 82 is a support pipe 88. The pipe 88 is prefereably fixed to the half-round sockets 80 and rotates with the furnace struc- .ture 18 within the sockets 82 over the frame 86. A stop member 90 extends upwardly from the rear of the frame 86 to serve as a stop to limit the angle through which the furnace structure 18 can be tilted.

For adjusting the tilt angle of the furnace structure 18, a turn buckle 92 is positioned with its end pivotally attached to the frame 86 and to the bottom support of the furnace structure 18. In this manner, the furnace chambers 58 and 60 may be tilted to any desired angle to adjust the incline of the tubular ovens supported within the furnace chambers.

The tubular ovens are represented by the numerals 94 and are of a generally hollow, cylindrical shape having open ends extending into the aligned front and rear holes 66 and 68 in the chambers 58 and 60. The ends of each oven are supported for rotation within the holes by front and rear coupling mechanisms 96 and 98, respectively. The coupling mechanisms 96 and 98 are preferably of the type described in the aforementioned co-pending patent application and reference should be made thereto for a detailed understanding of the structure of the coupling mechanisms. For the purposes of this specification, however, it is sufficient to state that the coupling mechanisms 96 and 98 extend through the front and rear holes 66 and 68 into the furnace chambers and are coupled to opposite ends of the ovens to support a pair of ovens 94 along the lobes of each furnace chamber with the rear end of each oven opening into one of the discharge ports 72 and an exhaust port 70. Heatexpanded ore passing from the open ends of the oven therefore, drop through the discharge ports while hot fumes with lightweight expanded ore particles travel upward from the ovens through the exhaust ports. The

expanded ore dropping through the discharge port 72 travels through the discharge duct 106 into the pit 15 while the lightweight expanded ore particle in the exhaust are collected by the recovery apparatus 22 and directed into the pit 15. v

The recovery apparatus 22 is of the type described in the afore-mentioned co-pending patent application and provides means for selectively collecting lightweight ore particles from the exhaust fumes and controlling the sizes of the particles thus collected. Reference should be made to the afore-mentioned patent application for a clear understandin of details of the recovery apparatus 22.

To produce the desired rotation of the ovens 94, a sprocket wheel 10?. is fixed to and around each front coupling assembly 96. The sprockets 1&2 form integral parts of a rotary drive mechanism which also includes a variable speed motor 104 mounted on the side of the furnace structure 18 with its drive shaft extending to a gear box 1%. The output shaft of the gear box 166 is coupled to a drive gear 198 in line with the sprockets 102. A continuous chain 11% passes around the drive gear 198, a pair of idler gears 112 and 114, and loops around the sprockets 102 in the manner illustrated in FIGURE 4, namely, around the left hand sprocket over the top of the next sprocket, around the bottom of the following sprocket and over the top of the right hand sprocket and thence back to the drive gear 108.

The drive gear 108 is rotated in a counterclockwise direction by the drive motor 194. Hence, the sprockets 102 and the associated tubular ovens 94 are rotated in the directions indicated by the arrows in FIGURE 4, to wit: the left hand oven of each pair of ovens is rotated in a counterclockwise direction while the right hand oven of each pair is rotated in a clockwise direction. This means that the ore in entering and passing along each left side oven rotates to and slides downward along the fourth quadrant of the oven while the ore in each right side oven rotates to and slides along the third quadrant of the oven. As will be discussed later, this is important to the uniform heating and complete expansion of the ore passing through the ovens.

The apparatus for heating the ovens is stationed above and along the outside of each pair of ovens and is adapted to establish downward extending flames along the sidewalls of the oven chambers. Preferably, the heating apparatus includes a number of longitudinally spaced refractory sleeves 116 stationed in generally vertical planes through openings in the arches 55 and supported on the top of the sides 52 of the base member 50 at opposite sides of the furnace chambers 58 and 60. The sleeves 116 are adapted to receive burner nozzles 11% coupled by flexible tubing 120 to a fuel supply assembly. The fuel supply assembly includes the pipe 88 which is coupled at one end to a fuel supply and capped at an opposite end. Separate fuel lines 122 and 124 extend from the left and right ends of the pipe 88 and are joined to each other above the inner upper surface of the furnace structure at 124. The joint 124 is closed as illustrated in FIGURE 3 to isolate the lines 122 and 124 from each other. Two pair of closed end manifolds 126 and 123 coupled to the fuel lines 122 and 128, respectively, extend above the furnace structure along the opposite sides of the chambers 58 and 69. The flexible tubes 120 are coupled to and extend downward from the manifolds 126 and 128 to provide fuel for the nozzles 118.

The amount of fuel supplied to the nozzles i118 and hence, the temperature within the furnaces 58 and 60, may be selectively regulated by a regulator valve 130 stationed within the pipe 88 below the furnace structure.

For igniting the fuels from the nozzles, the sidewalls 52 of the furnace structure are provided with openings 132. The openings 132 are sufliciently large to receive a torch for lighting the nozzles. Normally, the holes 132 are closed by blocks of refractory material 134 seated within the holes and including handles 136 providing a handgrasping means for moving the blocks into and out of the holes.

Once the nozzles 118 are ignited, flames pass from the nozzles downward along the sidewalls 52 of the chambers 58 and 61 By reason of the disposition of the inner faces of the chamber providing an internal heartshaped design, the flames swirl around the lower surfaces of the ovens and upward between and completely around the ovens as indicated by the arrows in FIGURE 3. The flames from the nozzles thus heat the lateral surfaces of the ovens from points immediately adjacent the nozzles around to and including the quadrants of the ovens containing the ore being expanded. Accordingly, equal oven surface areas are subjected to the flames prior to engaging the ore. This leads to a uniform heating temperature along the entire surfaces of the ovens within the furnace structure and together with a rotation of the ovens in the indicated directions has provided a substantial and unexpected improvement in the quality and percentage of ore particles expanded in the ovens of the present invention.

Further, by extending the sleeves and burner nozzles 11% through the upper sides of the furnace structure the sleeves as well as the burner nozzles may be easily removed for cleaning and maintenance. Also, the positioning of the nozzles above the furnace chambers prevents clogging of the nozzles by any foreign particles within the chambers to further insure continued uniform heating of the oven surfaces and even and complete expansion of the ores passing therethrough.

To further insure a uniform heating and complete expansion of ore particles passing through the ovens, the furnace structure of the present invention includes air scouring means for preventing the incrustation of expanded ore particles on the inner surfaces of the ovens. Such means are illustrated most clearly in FIGURES 2, 5, 6 and 7.

As represented, the air scouring means includes a generally diamond-shaped hollow scouring bar 138 stationed within and along each oven 94 with its upper apex 149 adjacent the upper surface of the oven. A rigid support rod 142 extends along and is secured to the upper inner surfaces of the scouring bar 138 as well as to the closed front and rear ends 144- and 146 of the scouring bar. Extending through the upper apex of the scouring bar 133 and through its associated rod 142 are a plurality of vertically extending pin holes 14 8. The pin holes are spaced evenly from each other and inclined upward toward the rear of the bar at approximately a 60 angle from longitudinal axis of the bar.

Secured to the rear end 146 of each scouring bar is a shaft 159. The shaft 156 extends through the rear coupling mechanism 98 for the associated oven and is supported for longitudinal sliding movement within a sleeve bearing 152.

Extending forward from the front end 144 of each scouring bar is a hollow shaft 154. The rear end of each hollow shaft 154 is fixed within an opening .156 in the front end of the scouring bar while the open front end of the shaft passes through the front coupling mechanism 96 of the associated oven 94 where it is supported for longitudinal sliding movement within a sleeve bearing 158.

The open front ends of each hollow shaft 154 is fixed to a rigid, hollow, cross connecting tube 160 having a closed right end and a left end coupled to an air supply line 162 from a source of compresed air. Thus, air from the source passes through the tube 166 into each of the hollow shafts 154 to the scouring bars 138. In the scouring bars, the air jets upward through the pin holes 148 against the inner surfaces of the associated ovens. As the ovens rotate, the air jets effectively scour the inner surfaces of the ovens to prevent expanded ore particles from sticking to the inner surfaces of the ovens and interfering with the uniform heating of the ore particles passing through the ovens.

In the present invention, the air scouring action is further improved by longitudinally oscillating the scouring bars within the ovens and by causing the air to be supplied intermittently to the scouring bars to produce a series of intermittent air jets for effectively air blasting the inner surfaces of the ovens.

To oscillate the scouring bars 133 as the ovens rotate, a drive mechanism 164 is coupled between the tube 16% and the rotary drive apparatus for the ovens 94. The drive mechanism 164 comprises a shaft 166 fiXEd to-and extending forward from the idler gear 114 of the rotary drive apparatus for the ovens 94. The forward end of of the shaft 166 is stationed within a gear box 168' having laterally extending output shafts 176 from opposite sides of the gear box.

Fixed to the ends of the shafts 170 are identical crank mechanisms 172. The crank mechanisms each include a relatively short linkage arm 174 having one end secured for rotation in a generally vertical plane with the shaft 170 and an opposite end pivotally coupled by a pin 176 to a relatively long, vertically extending arm 178. The lower end of the arm 178 is, in turn, pivotally coupled by a pin 186 to a crank arm 132 fixed to a cross bar 184. The ends of the cross bar 184- are journalled within a pair of support plates 186 and 188 to the front end of the furnace structure to support the bar for rotation with the crank arm 1S2.

Secured for rotation to the bar 184 is a drive arm 190 having its upper end rotatably'coupled by a pin 192 to a connecting arm 1%, the end of which is hinged to the air tube 160.

In operation, the counterclockwise rotation of the idler gear 114 with the rotation of the ovens 4 produces a clockwise rotation of the shafts 17 t and hence an up-down rocking movement of the crank arm 182 and an oscillatory arcuate turning of the cross bar 184-. The oscillatory turning of the bar 184 produces a rocking of the drive arm 190 between a forward position indicated by the dotted outline 1% in FIGURE 6 and a rearward position indicated by the broken outline 198. In the forward position, the arm 190 carries the connecting arm 194 and the air tube 160 away from the furnace structure to slide the hollow shafts 154 and hence the scouring bars 138 toward the front ends of the oven 94. Movement of the drive arm 190 to the rear position causes the connecting arm 194 and the air tube 160 to move to a position adjacent the outer end of the furnace structure. This produces a rearward movement of the scouring bars 138 within the ovens 94. Thus, as the ovens 94 rotate in the directions indicated in FIGURE 4, the rotation of the idler gear 114 through the rotary drive mechanism 164 produces a longitudinal oscillation of the securing bars 138 within the ovens 94. As the scouring bars oscillate within the ovens 94, the air jets travel along the upper inner surfaces of the ovens to scour the surfaces and prevent incrustation of expanded ore particles. 7

As the drive arm I90 oscillates between its forward and rearward positions, it is adapted to selectively actuate a bi-stable switch 269 to open and close a solenoid valve 202 in the air line 162. In particular, when the drive arm 194- reaches its forward position, it engages and actuates a push-button switch 294 electrically coupled to the inputs 2% of the bi-stable switch 200. The actuation of the switch 204 causes the bi-stable switch to switch to a first stable state generating an output signal on the output leads 206 to the solenoid valve 2%2 which effects an opening of the valve to pass air into the scouring bars. Air continues to pass into the scouring bars 138 as the arm 190 travels to its rearward position. In the rearward position, the arm 1% engages and actuates a push-button switch 208 electrically coupled by input leads 210 to the bi-stable switch 200. The actuation of the switch 203 causes the bi-stable switch to switch to a second stable state effecting a closing of the solenoid valve to block air flow to the scouring of the bars as they travel forward within the ovens 94. In this manner, intermittent blasts of air are jetted through the pin holes 142 as the scouring bars travel rearward andforward within the ovens 94. The sudden blasts of air jets improve the scouring operation and conserve compressed air for more efficient and longer operation of the apparatus.

In view of the foregoing, it is appreciated that the present invention provides an improved furnace structure which insures uniform heating and complete expansion of expandable ore particles within rotating tubular ovens housed by the structure while preventing clogging of the burner nozzles for heating the ovens and incrustation of expanded ore particles on inner surfaces on the ovens.

In the foregoing specification, a specific embodiment has been described. Modifications, of course, may occur to those skilled in the art without departing from the spirit of the invention. Therefore, it is intended that the present invention he limited in scope only by the following claims.

We claim:

1. A furnace assembly for expanding crushed, heat-expandable ores, comprising:

a furnace structure including elements of refractory material defining a pair of separated, open-ended, elongated furnace chambers each having an inverted generally heart-shaped cross section with right and left side lobes;

a tubular oven extending along and supported for rotary movement within each lobe of said furnace chambers;

a plurality of generally vertical burner nozzles supported in said furnace structure above each of said ovens and spaced along opposite longitudinal side surfaces of said furnace chamber;

a fuel line system for supplying fuel to said burners including a pipe under and extending between opposite sides of said furnace structure, fuel-carrying ducts from one end of said pipe to each nozzle associated with one of said furnace chambers, fuel-carrying ducts from an opposite end of said pipe to each nozzle associated with the other of said furnace chambers, and a fuel supply line from a fuel source to said P P means including said pipe for supporting said furnace structure in a position wherein said ovens are tilted downward from the front toward the rear of said furnace structure;

rotary drive means coupled to said ovens for rotating said ovens within said furnace chambers;

adjustable means for feeding heat expandable ore at a common rate into a front end of each of said ovens;

and means for scouring the inner surfaces of said ovens as they rotate within said furnace chambers.

2. A furnace assembly for expanding crushed, heatexpandable ores, comprising:

a furnace structure including elements of refractory material defining a pair of separated, open-ended, elongated furnace chambers each having an inverted generally heart-shaped cross section with right and left side lobes;

a tubular oven extending along and supported for rotary movement within each lobe of said furnace chambers;

a plurality of generally vertical burner nozzles supported in said furnace structure above each of said ovens and spaced along opposite longitudinal side surfaces of said furnace chamber;

a fuel line system for supplying fuel to said burners including a pipe under and extending between opposite sides of said furnace structure, fuel-carrying ducts from one end of said pipe to each nozzle associated with one of said furnace chambers, fuelcarrying ducts from an opposite end of said pipe to each nozzle associated with the other of said furnace chambers, and a fuel supply line from a fuel source to said pipe;

means including said pipe for supporting said furnace structure in a position wherein said ovens are tilted downward from the front toward the rear of said furnace structure;

rotary drive means coupled to said ovens for rotating said ovens within said furnace chambers;

and means for feeding heat-expandable ore into a front end of each of said ovens.

3. A furnace assembly for expanding crushed, heatexpandable ores, comprising:

a furnace structure including elements of refractory material for defining an open-ended, elongated furnace chamber having an inverted generally heart-shaped cross section with communicating right and left side lobes;

a tubular oven extending along and supported for rotary movement within each lobe of said furnace chamber;

a plurality of generally vertical burner nozzles supported in said furnace structure above each of said ovens and spaced along opposite longitudinal side surfaces of said furnace chamber, said nozzles opening downward along said side surfaces to direct flames downward therealong to follow the heart-shaped contour of said chamber and to swirl upwardly betWeen and around said ovens;

means for supplying fuel to said burner nozzles;

means for supporting said furnace structure in a position wherein said ovens are tilted downward from the front toward the rear of said furnace structure;

rotary drive means coupled to said ovens for rotating said ovens within said furnace chambers;

and means for feeding heat-expandable ore into a front end of each of said ovens.

4. A furnace assembly for expanding crushed, heatexpandable ores, comprising:

a furnace structure including elements of refractory material defining a pair of separated, open-ended, elongated furnace chambers each having an inverted generally heartshaped cross section with right and left side lobes;

a tubular oven extending along and supported for rotary movement within each lobe of said furnace chamber;

a plurality of generally vertical burner nozzles supported in said furnace structure above each of said ovens and spaced along opposite longitudinal side surfaces of said furnace chamber;

means for supplying fuel to said burner nozzles;

means for supporting said furnace structure in a position wherein said ovens are tilted downward from the front toward the rear of said furnace structure;

rotary drive means coupled to said ovens for rotating said ovens within said furnace chambers;

means for feeding heat-expandable ore into a front end of each of said ovens;

and means for scouring the inner surfaces of said ovens as they rotate within said furnace chambers.

5. A furnace assembly for expanding heat-expandable ores, comprising:

a furnace structure including elements of refractory material defining an open-ended elongated furnace chamber;

a tubular oven extending along and supported for rotation within said furnace chamber;

burner means in said furnace structure for heating lateral surfaces of said oven;

means adapted to support said furnace structure in a position wherein said oven is tilted downward from the front toward the rear of said furnace structure;

rotary drive means coupled to said oven for rotating said oven within said furnace chamber;

means for feeding heat-expandable ore into a front end of said oven to travel along lower inner surfaces of said oven toward said rear of said furnace;

and means spaced from said ore as it travels through ores, comprising:

a furnace structure including elements of refractory material defining an open-ended elongated furnace chamber;

a tubular oven extending along and supported for rotation within said furnace chamber;

burner means in said furnace structure for heating lateral surfaces of said oven;

means adapted to support said furnace structure in a position wherein said oven is tilted downward from the front toward the rear of said furnace structure;

rotary drive means coupled to said oven for rotating said oven within said furnace chamber;

means for feeding heat-expandable ore into a front end of said oven to travel along lower inner surfaces of said oven toward said rear of said furnace;

tubular means within said oven having openings therein;

means supporting said tubular means within and along said oven with said openings adjacent and facing an ore-free inner surface of said oven;

and means for supplying air to said tubular means to produce jets of air through said openings directed at said ore-free inner surface of said oven.

7. An assembly for expanding heat-expandable ores,

comprising:

a furnace structure including elements of refractory material defining an open-ended elongated furnace chamber;

a tubular oven extending along and supported for rotation Within said furnace chamber;

burner means in said furnace structure for heating lateral surfaces of said even;

means adapted to support said furnace structure in a position wherein said oven is tilted downward from the front toward the rear of said furnace structure;

rotary drive means coupled to said oven for rotating said oven within said furnace chamber;

means for feeding heat-expandable ore into a front end of said oven to travel along lower inner surfaces of said oven toward said rear of said furnace;

tubular means within said oven having openings theremeans supporting said tubular member within and 'along said oven with said openings adjacent and facing an ore-free inner surface of said oven;

means for oscillating said tubular means within said oven;

and means for supplying air to said tubular means to produce jets of air through said openings directed at said ore-free inner surface of said oven.

8. An assembly for expanding heat-expandable ores,

comprising:

a furnace structure including elements of refractory material defining an open-ended elongated furnace chamber;

a tubular oven extending along and supported for rotation within said furnace chamber;

burner means in said furnace structure for heating lateral surfaces of said oven;

means adapted to support said furnace structure in a position wherein said oven is tilted downward from the front toward the rear of said furnace structure;

rotary drive means coupled to said oven for rotating said oven within said furnace chamber;

means for feeding heat-expandable ore into a front end of said oven;

tubular means within said oven having openings theremeans for oscillating said tubular means within said oven;

and means for intermittently supplying air to said tubu- 1 1 lar means to produce intermittent jets of air directed at the inner surfaces of said oven.

9. An assembly for expanding heat-expandable ore,

comprising:

a furnace structure including elements of refractory material defining an open-ended elongated furnace chamber;

a tubular oven extending along and supported for rotation within said furnace chamber;

burner means in said furnace structure for heating lateral surfaces of said oven;

means adapted to support said furnace structure in a position wherein said oven is tilted downward from the front toward the rear of said furnace structure;

rotary drive means coupled to said oven for rotating said oven within said furnace chamber;

means for feeding heat-expandable ore into a front end of said oven;

tubular means Within said oven having openings theremeans coupled to said rotary dirve means responsive to operation thereof for oscillating said tubular means within said oven as said oven rotates;

and means for supplying air to said tubular means to produce jets of air directed at the air surfaces of said oven.

10. An assembly for expanding heat-expandable ores,

comprising:

a furnace structure including elements of refractory material defining an open-ended elongated furnace chamber;

a pair of tubular ovens extending along said furnace chamber and supported side by side for rotation within said furnace chamber;

burner means in said furnace structure for heating lateral surfaces of said oven;

means adapted to support said furnace structure in a position wherein said ovens are tilted downward from the front towards the rear of said furnace structure;

12 rotary drive means coupled to said tubular ovens for rotating said ovens Within said furnace chamber; means for feeding heat-expandable ore into the front end of each oven;

a tube positioned within each of said ovens and having openings therein;

means for simultaneously oscillating said tubes within said ovens;

and means for supplying air to said tubes to produce jets of air directed at the inner surfaces of said ovens.

11. The assembly of claim 10 wherein said means for simultaneously oscillating said tubes includes drive means coupled to said rotary drive means and responsive to the operation thereof for oscillating said tubes as said ovens rotate.

12. The assembly of claim 11 wherein said means for supplying air to said tubes is adapted to intermittently supply air to said tubes such that intermittent air jets are directed at the inner surfaces of said ovens.

References Cited by the Examiner UNITED STATES PATENTS 820,088 5/1906 Boileau 263-34 1,419,131 6/1922 Foster 26334 1,974,250 9/1934 Osborn 34--127 X 2,150,532 3/1939 Wiegand et a1 26334 2,305,938 12/1942 Turnbull 34-127 X 3,144,245 8/1964 Martin 263-34 FOREIGN PATENTS 554,584 6/1923 France.

720,694 12/ 1954 Great Britain.

898,316 6/ 1962 Great Britain.

FREDERICK L. MATTESON, JR., Primary Examiner.

JAMES W. WESTHAVER, Examiner.

D. A. TAMBURRO, Assistant Examiner. 

1. A FURNACE ASSEMBLY FOR EXPANDING CRUSHED, HEAT-EXPANDABLE ORES, COMPRISING: A FURNACE STRUCTURE INCLUDING ELEMENTS OF REFRACTORY MATERIAL DEFINING A PAIR OF SEPARATED, OPEN-ENDED, ELONGATED FURNACE CHAMBERS EACH HAVING AN INVERTED GENERALLY HEART-SHAPED CROSS SECTION WITH RIGHT AND LEFT SIDE LOBES; A TUBULAR OVEN EXTENDING ALONG AND SUPPORTED FOR ROTARY MOVEMENT WITHIN EACH LOBE OF SAID FURNACE CHAMBERS; A PLURALITY OF GENERALLY VERTICAL BURNER NOZZLE SUPPORTED IN SAID FURNACE STRUCTURE ABOVE EACH OF SAID OVENS AND SPACED ALONG OPPOSITE LONGITUDINAL SIDE SURFACES OF SAID FURNACE CHAMBER; A FUEL LINE SYSTEM FOR SUPPLYING FUEL TO SAID BURNERS INCLUDING A PIPE UNDER AND EXTENDING BETWEEN OPPOSITE SIDES OF SAID FURNACE STRUCTURE, FUEL-CARRYING DUCTS FROM ONE END OF SAID PIPE TO EACH NOZZLE ASSOCIATED WITH ONE OF SAID FURNACE CHAMBERS, FUEL-CARRYING DUCTS FROM AN OPPOSITE END OF SAID PIPE TO EACH NOZZLE ASSOCIATED WITH THE OTHER OF SAID FURNACE CHAMBERS, AND A FUEL SUPPLY LINE FROM A FUEL SOURCE TO SAID PIPE; MEANS INCLUDING SAID PIPE FOR SUPPORTING SAID FURNACE STRUCTURE IN A POSITION WHEREIN SAID OVENS ARE TILTED DOWNWARD FROM THE FRONT TOWARD THE REAR OF SAID FURNACE STRUCTURE; ROTARY DRIVE MEANS COUPLED TO SAID OVENS FOR ROTATING SAID OVENS WITHIN SAID FURNACE CHAMBERS; ADJUSTABLE MEANS FOR FEEDING HEAT EXPANDABLE ORE AT A COMMON RATE INTO A FRONT END OF EACH OF SAID OVENS; AND MEANS FOR SCOURING THE INNER SURFACES OF SAID OVENS AS THEY ROTATE WITHIN SAID FURNACE CHAMBERS. 